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CVE-2024-56647

Description

In the Linux kernel, the following vulnerability has been resolved:net: Fix icmp host relookup triggering ip_rt_bugarp link failure may trigger ip_rt_bug while xfrm enabled, call trace is:WARNING: CPU: 0 PID: 0 at net/ipv4/route.c:1241 ip_rt_bug+0x14/0x20Modules linked in:CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.12.0-rc6-00077-g2e1b3cc9d7f7Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014RIP: 0010:ip_rt_bug+0x14/0x20Call Trace: ip_send_skb+0x14/0x40 __icmp_send+0x42d/0x6a0 ipv4_link_failure+0xe2/0x1d0 arp_error_report+0x3c/0x50 neigh_invalidate+0x8d/0x100 neigh_timer_handler+0x2e1/0x330 call_timer_fn+0x21/0x120 __run_timer_base.part.0+0x1c9/0x270 run_timer_softirq+0x4c/0x80 handle_softirqs+0xac/0x280 irq_exit_rcu+0x62/0x80 sysvec_apic_timer_interrupt+0x77/0x90The script below reproduces this scenario:ip xfrm policy add src 0.0.0.0/0 dst 0.0.0.0/0 \ dir out priority 0 ptype main flag localok icmpip l a veth1 type vethip a a 192.168.141.111/24 dev veth0ip l s veth0 upping 192.168.141.155 -c 1icmp_route_lookup() create input routes for locally generated packetswhile xfrm relookup ICMP traffic.Then it will set input route(dst->out = ip_rt_bug) to skb for DESTUNREACH.For ICMP err triggered by locally generated packets, dst->dev of outputroute is loopback. Generally, xfrm relookup verification is not requiredon loopback interfaces (net.ipv4.conf.lo.disable_xfrm = 1).Skip icmp relookup for locally generated packets to fix it.

CVE-2024-56647

Description

POC

Reference

Github